究其原因，這是個(gè)Oracle的bug,Bug 2365821,可見Metalink上的ORA-4043 On DBA_* Views If They Are Described In Mount Stage [ID 296235.1]，受影響的數(shù)據(jù)庫版本：Oracle Server – Enterprise Edition – Version: 8.1.7.4 to 11.2.0.1 – Release: 8.1.7 to 11.2，This problem can occur on any platform.
2019-06-24
uesr_constraints這個(gè)字典放了很多表的約束及其信息，所以記得加s。很多字典都是這樣：dba_users用戶字典、dba_tablespaces表空間字典、dba_data_files數(shù)據(jù)文件字典。
2017-04-21
因?yàn)槟鉩onstraint沒有加s，這個(gè)是復(fù)數(shù)形式，因?yàn)椴恢皇侵挥幸粭l字段所以要用復(fù)數(shù)形式
2016-11-27
?描述：當(dāng)數(shù)據(jù)庫處于MOUNT狀態(tài)時(shí)，如果試圖去訪問DBA_之類的數(shù)據(jù)字典表時(shí)，數(shù)據(jù)庫會(huì)報(bào)出ORA-04043錯(cuò)誤！即使，接下來，ALTER DATABASE OPEN，將數(shù)據(jù)庫置于OPEN狀態(tài)，再嘗試去查看DBA_之類的數(shù)據(jù)字典表時(shí)，數(shù)據(jù)庫依然會(huì)報(bào)出ORA-04043錯(cuò)誤！解決的辦法有兩個(gè)：
????????? ① 重啟數(shù)據(jù)庫；
????????? ② 刷出共享池：ALTER SYSTEM FLUSH SHARED_POOL
究其原因，這是個(gè)Oracle的bug,Bug 2365821,可見Metalink上的ORA-4043 On DBA_* Views If They Are Described In Mount Stage [ID 296235.1]，受影響的數(shù)據(jù)庫版本：Oracle Server – Enterprise Edition – Version: 8.1.7.4 to 11.2.0.1 – Release: 8.1.7 to 11.2，This problem can occur on any platform.